Hydrogen gas is the object of significant research as an alternate fuel source to fossil fuels. Hydrogen is attractive because (i) it can be produced from many diverse energy sources, (ii) hydrogen has a high energy content by weight (about three times more than gasoline) and (iii) hydrogen's zero-carbon emission footprint—the by-products of hydrogen combustion being oxygen and water.
However, hydrogen has physical characteristics that make it difficult to store in large quantities without taking up a significant amount of space. Despite hydrogen's high energy content by weight, hydrogen has a low energy content by volume. This makes hydrogen difficult to store, particularly within the size and weight constraints of a vehicle, for example. Another major obstacle is hydrogen's flammability and the concomitant safe storage thereof.
Known hydrogen storage technologies directed to high pressure tanks with compressed hydrogen gas and/or cryogenic liquid hydrogen storage have shortcomings because the risk of explosion still exists. These approaches require pressurized containers that are heavy and also require high energy input—features that detract from commercial viability.
Metal alloy hydrogen storage is based on materials capable of reversibly absorbing and releasing the hydrogen. Metal alloy hydrogen storage provides high energy content by volume, reduces the risk of explosion, and eliminates the need for high pressure tanks and insulation devices. Metal alloy hydrogen storage, however, struggles with low energy content by weight.
The art recognizes the need for safe, reliable, compact, and cost-effective hydrogen storage technology. The art further recognizes the need for continued development of metal alloy hydrogen storage.